I will take the ASVAB soon. Any good tips/advice for taking the test (any good ways to study, most important areas, etc.)?

Most important math.

Get good rest the night before the test. Easy on the coffee the morning before the test. Eat a low carb breakfast. Relax your body and mind before the test starts. Read and follow ALL of the instructions. RTFQ (read the fine question, completely). RTFA (read the fine answers, all of them, completely, before selecting one). There are no trick questions. If the test appears to ask a straight forward question with a fairly obvious answer, then that's what it is. Follow RTFQ and RTFA and don't read too much into a question.

The word math is 80% of the test, study.

I found a couple apps for my phone that I used. They were great for me because they were able to identify my weak areas and help me focus on it. Just do your research and try not to overthink it!!

GT, get that one high.

Get plenty of rest before the test, pay attention to your time limits. It's not a difficult test. There are prep books you can get, your recruiter should be able to point you in the right direction.

Obviously a long time ago (1987) but when I joined my recruiter gave me a practice test which I did really well on but the practice test wasn't timed on a per-section basis so when I took the real test I bombed some sections (like coding speed) because I wasn't prepared to have a limited amount of time for those sections.

"Coaching" by your recruiter is illegal, or against the military (MEPCOM) rules. There are many ASVAB prep books out there. You can't do much about the functional areas of the test such as Mech. Comprehension, Electronic Information etc. You can study and maybe bring those up a few points though. The test has probably changed but the four parts that determined your AFQT were Arithmetic Reasoning (AR - math problems), Word Knowledge (WK - vocabulary), Paragraph Comprehension (PC - understanding the meaning of a short passage), and Numerical Operations (NO - speed math). The formula for AFQT was AR+WK+PC+ .5 times NO, equals a raw score that converts to your AFQT, The AFQT determines what Mental Category you fall in Cat 1 - 4. The higher you score the lower category, Cat 1 being the best category. These will determine your enlistment options. The recruiters can give you pre-screening tests and pointers but are not allowed to coach you. Talk to a recruiter. They usually keep some ASVAB prep books laying around, or you can find them in libraries. All but the AFQT are used to determine eligibility for specific MOSs. The AFQT is the one that matters most getting in unless you are eyeballing a special field. After that the GT and GCT determine general cutoffs for officer programs and some MOSs etc. Hope this helps.

PV2 J M Search on ASVAB and find ASVAB resources. Get a good nights sleep and be focused when you take the test.

http://www.military.com/join-armed-forces/asvab/asvab-study-tips.html

They want to know your general knowledge level so what's the point of studying for it?